1. Field of the Invention
The present invention relates to a data storage device, or disk drive, for receiving a removable disk cartridge. More particularly, the present invention relates to a movable platform which has compliant retainers for the rotor of the spindle motor.
2. Description of the Prior Art
Removable disk cartridges for storing digital electronic information typically comprise an outer casing or shell that houses a rotatable recording medium, or disk, upon which electronic information can be stored. The cartridge shell often comprises upper and lower halves that are joined together to house the disk. The disk is mounted on a hub that rotates freely within the cartridge. When the cartridge is inserted into a disk drive a spindle motor in the drive engages with the disk hub in order to rotate the disk within the cartridge.
Disk drives for receiving removable disk cartridges must have some mechanism for bringing the hub of a disk cartridge into engagement with the spindle motor of the disk drive and for maintaining tight tolerances between the cartridge hub, spindle motor and magnetic head actuator of the disk drive. U.S. Pat. Nos. 5,617,397 and 5,805,555, Jones, et al., Movable Platform For a Disk Drive, describe such a mechanism. This disk drive commonly referred to as the ZIP drive. This drive has a ball-bearing spindle motor. Ball-bearing motors have limited rotor movement in the Z, or axial direction. The ball-bearing motors used in the ZIP drive retain the rotor with the bonded and preloaded ball-bearings.
Recently spindle motors of the sleeve bearing type have been used. For example, CD/ROM motors use sleeve-bearing spindle motors. A sleeve-bearing needs a feature which stops the rotor assembly from coming out of the magnetic attraction range between the rotor magnet and the stator. CD/ROM motors having sleeve-bearing motors use various of types of retainers to limit the Z-axial movement of the rotor. These designs typically have one or two parts which are used for retainers. The addition of these parts is expensive. Some retainers and CD/ROM motors require a longer shaft to accommodate a variation of the retainer design.